Population of Corbicula japonica in Lake Jusan increased steeply in 2008. In order to explain the increase, we focused on the environmental conditions of spawning season. The dynamic energy budget (DEB) simulation indicates that C. japoica were able to spawn every year, but they waited for suitable spawning temperature. After spawned, eggs need a certain salinity transforming to larva and juvenile stage. Results of a vertical one-dimensional water quality simulation show that in 2007 the duration of spawning temperature was longer than in the other years, indicating a higher opportunity for all adult C. japonica to spawn. Also, the daily average salinity was close to the ideal salinity transferring eggs to larva and juvenile stage. These two parameters are supposed to be the main factors affecting the high population in 2008.

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This study was conducted monthly investigation of R. philippinarum density along with measurement of DO, temperature and salinity in Omaehama beach from 2006 to 2008. Filtered function and recovery process of R. philippinarum were measured in hypoxic and anoxic condition. R. philippinarum which exposed by hypoxia and anoxic water was put in the sufficient oxygen water and feeding activity was measured every few days. It is revealed that hypoxic water decreased a filtered function of R, philippinarum for a long term. In the anoxic water, the number of R. philippinarum dying increased and filter-feeding activity never recovered. Consequently, it indicated that filter-feeding activity of R. philippinarum could not be expected even though it would survive in hypoxic and anoxic water

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A mobile oceanographical observation platform, which can measure vertical distributions of water qualities of coastal water and velocities, has been developed in this study. This system was deployed 12 km off Abukuma river mouth in Sendai sound in summer of 2010. The observation results have shown the characteristic three layer structures; the surface layer with low salinity and high water temperature, the middle layer with the salinity maximum, high DO concentration and large mean diameter of SPM and the bottom layer with stable lower temperature and relative high Chlorophyll a. The comparisons of these vertical distributions with the results of water quality survey around Sendai sound and Jyoban coast have suggested that the three layer structure was generated by the intrusion of offshore saline water into the middle layer of Sendai sound.

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Sea routes were buried with large amount of sand transported by Typhoon No.0423. The dredged sand for recovering the routes were dumped into the sea in order to develop rich fisheries. Surveys of bottom sediment, benthic creature, fishing, bathymetry etc. were conducted in this study. From the results, it is found that any negative impacts caused by dredged sand dumping have not been observed, and that the study area becomes a rich habitat for marine resources.

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It is necessary to catch young scallops deliberately for sustainable business of scallop culture, because quantity of young scallops, which is taken by fishermen, affects to fishery of scallops and scallop culture environment directly. We are studying a simulation method to estimate behavior of young scallops. This paper focuses on setting methodology of spawning period and growth speed of scallop in order to optimize input parameters of the simulation. Field data sets were used to evaluate spawning period and growth speed. Simulation with the spawning period and the growth speed gave reasonable results qualitatively.

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The authors started field observation mainly around the Musashi Bank in 2009, in connection with a planning of fishing ground development in the exclusive economic zone around Hokkaido. It considered the migration pathway of the larva of alaska pollack that was the target of the resource conservation. From the survey, it was found that the lack of the nutrient salt on the surface was not recovered in autumn. As a result, the primary production rate in summer was about 36.6 (mg-C/m²/day), the rate in autumn decreased to 29.04, and that in winter along the pathway was 95.4. It was suggested that Tsushima Warm Current along the Hokkaido coast prevented de-stratification in autumn and it caused the lack of the nutrient salt in the photic layer. Assuming enough nutrient salt for photosynthesis, the calculated rate increased up to about 102.3.

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Styela plicata inhabits the area along the shore, it is filter feeder and attaches to the surface of coastal structure wall. This study aims to clarify influence of water temperature and salinity on suspended solids feeding activity of S. plicata. When water temperature decreased from 20℃ to 10℃, the amount of filtered water and food consumption of S. plicata decreased to about half. On the other hand, both made a little difference when water temperature increased from 20℃ to 25℃. In addition, the amount of filtered water and food consumption of S. plicata increased in proportion to wet weight, but when salinity decreased from 30 psu to 20 psu, both decreased, and there were not the relations with the wet weight, and it was with a constant value.

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The Amagasaki Canal, an enclosed waters, have been polluted and eutrophication and hypoxic condition occurred chronically. To restore the aqueous environment of the canal, a water purifying plant was designed and substantiative experiment have been conducted by Amagasaki Sea Blue Project. However, the environmental impact on the sea-bed by the organic load from sessile organisms has been concerned. To reduce the organic load, formation of air layer at the bottom of the structure is regarded as a promising method. In this study, the method was evaluated by the amount of sessile organisms, organic load, and oxygen consumption necessary for the organism resolution. As a result, sessile organisms adhesion was completely inhibited, all the organic load by sessile organisms was reduced, and the oxygen consumption was suppressed.

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The purpose of this study is to develop a pelagic ecosystem model considering microbial processes coupled with the non-hydrostatic flow field in estuaries and coasts. The model was applied to the ecosystem simulation in Ise Bay and was evaluated its reproducibility for field observational data. Calculation results also revealed that the bacterial production corresponded to 18.2 % of the primary production though the bacterial biomass accounted for only 3.9 % of the total. Additionally, the bacterial respiration corresponded to 50 % of the total oxygen consumption in the bottom layer.

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To investigate major causes of the variability of the short-necked clam (Ruditapes philippinarum) resources in Ise Bay in the 1990s, we carried out a long-term numerical simulation using the 3D hydrodynamic and biogeochemical cycle model coupled with the life cycle model of the short-necked clam. The calculated results of the clam yields agreed with the observed variability; the decrease trend during 1990-1996 and the increase trend during 1997-2000. The results indicated that the clam yields mainly depended on the pelagic-larval settlement. The key factor of the pelagic-larval settlement was the change in the spawning rate depending on the sea temperature in the spring spawning seasons. The sea temperature in the spring spawning season was considered to be the major cause of the clam yield variability during 1990-2000 in Ise Bay.

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The objective of this study is to suggest a new method to estimate the settling velocity of mud flocs. The settling velocity is estimated based on the particle size distribution measured by Laser Diffraction Particle Size Analyzer (SHIMADZU: SALD-2000J). The accuracy and validity of the suggested method were investigated by comparing with the results obtained from Monte Carlo simulation. The relative errors are about 5 % when distilled water was used, and it becomes to be equal to 10 % (while 20 min) when salt water was used. Therefore, it is considered that the accuracy of the suggested method is high. These results suggest that the suggested method is valid for estimating the settling velocity of mud flocs that have different organic matter contents either in distilled water or salt water conditions.

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Many concrete and steel structures near shoreline are damaged severely by generated salt spray from sea surface. To reduce the transportation of salt spray near shoreline is effective method of prevention of salt damage. In this study, to discuss the effect of the structure on the reduction of salt spray concentration, experiments of transportation of salt spray were carried out. The wind velocity and the distribution of salt spray concentration around the permeable structures were measured in the wind tunnel. In this result, the structure that set up filters can effectively reduce the transportation of salt spray concentration, the experiment data showed that the decrease of salt spray concentration is influenced from the salt amount of adhesion of structures.

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Sea salt spray consists of small particle of seawater, generated by interaction of wave and wind. Its transportation is also affected by wind distribution, geographical condition and configuration of structure. To decrease sea salt spray concentration in the atmosphere is effective measure of prevention of the salt damage. In this study, to clarify the effect of decrease of sea salt spray concentration around permeable structure, field measurements were carried out. Numerical calculation of transportation of sea salt spray and wind field were also carried out. In those results, the permeable structure can reduce transportation of sea salt spray concentration.

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Field observation of the groundwater fluctuation has been conducting with the aim to obtain better understanding of groundwater dynamics in coastal sand-dune environment. Ogata beach in Joetsu coast was selected as field observation location. The Ogata sand dune (20km in length, the maximum of 1km in width, the maximum height of 30m) which is the layered structure of new and old dunes is distributed along the margin of Takada plain. The field observations and analysis of the tide and beach groundwater changes for particular points along beach profile, revealed interesting characteristics, include: strong correlation between tidal and beach groundwater fluctuation and so on. As a results, fresh groundwater supply in terms of steady flow theory is estimated to amount from 13.3 to 79.9m³/day per meter of beach width.

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The objective of this study is to estimate the turbidity distribution by using the AVNIR-2 data of 10m resolution in Sendai Bay after Great East Japan Earthquake. As a result, the following matters were clarified. The brown or black water distribution and destroyed oyster bed pieces and several km scales eddy were qualitatively shown from RGB image of AVNIR-2 around the bay after the earthquake. Moreover, the NPSS estimation method by AVNIR-2 LCI (Linear Combination Index) was examined by handling the bio-optical model. A significant strong correlation between AVNIR-2 LCI and NPSS was observed. The relation was validated by an actual AVNIR-2 image and the measurement turbidity. It was estimated to have distributed the at least high density up to about 10km offshore murky waters from continental areas around the bay after the Earthquake from the turbidity map finally made from AVNIR-2.

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To evaluate accurately temporal variations of floating-litter transport L in rivers, we present a new rating curve for L using temporal variation rate in water elevation H. For this purpose, we measured L in Edogawa River under two flooding events using a rectangle frame for directly collecting floating litters and a video imaginary monitoring for recording floating litters. The measured results indicate that the peak of the floating-litter transports appeared in the rising stage of the flooding and the temporal variations of L during the flooding are similar to those of H. It should be also noted that a new rating curve using the correlation between L and H has higher accuracy for evaluation of L than a primitive rating curve using L-Q relations in which Q means river discharge.

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The purpose of this study is to show the damping effect of the wave force by submerged plants in lakes and how the damping effect of it have been affected by differences with or without submerged plants and their rate. On survey line, which length was 400m from lakeside to offing, in Biwa Lake, we recorded continuously the wave height by the submerged plants at 5 points using pressure instrumentations. As a result, the damping effect was due to the plant cover ratio and the depth. On the maximum damping decreased by a factor of 0.71 compared with the case without the plants when the plant cover ratio was 100%. Moreover, we suggested how to calculate the damping factor by between the plant cover ratio and a density factor(kρ) of the plants.

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In this study, a floating device for improvement of the sea environment in a semi-enclosed bay has been developed, which is driven by renewable wave energy. As a preliminary study, under the assumption that the floating device was fixed to the water surface, several cross sections of the floating device derived from the previous study were examined to ensure the effectiveness of vertical mixing of sea water in comparatively deep sea. The major driving force of a device for vertical mixing of sea water is the piston mode wave motions in the water chamber located at the center of the body. In order to develop an effective floating device for vertical mixing of sea water, the influence of wave induced motions of the selected floating device on the effectiveness was examined experimentally.

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Waste gypsum-derived hemihydrate plaster (HP) was tested as a water absorber for shear thickening of dredged soil (DS) using decarburization slag (DCSL). HP was capable of adjusting apparent water content of DS, and the use of HP resulted in 60% reduction in the amount of DCSL required to meet the target Vane shear stress (0.5 kN/m²). As the total dose of thickening agents, the combinational use of HP and DCSL achieved 40% less as compared to the case of DCSL sole use. After immersing the treated DS into the artificial sea water, Vane shear stress increased during 30 days. The shear thickening effect of DCSL particles was dependent on grain size, and the fractions less than 2 mm-diameters played a prominent role. Finally, a simple additive model was proposed to expect the shear thickening effect of DCSL on DS.

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A laboratory experiment using the water of the Doi river was carried out to propose a reaction model of hydrogen sulfide and dissolved oxygen. Effective supply method of oxygen-rich water into the river bottom was investigated for the purpose of remediation of severe hypoxic condition through a series of experiments using a density flow model combined with the proposed reaction model. It was found that hydrogen sulfide of bottom layer mixed by induced flow by density difference and reduced by oxidation reaction. Further, it was found that water supply from multiple points was effective for wide improvement of river water under the same total amount of supply water.

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Although mudflat ecosystem may be influenced due to environmental impacts of terrestrial and coastal waters, there has been little information on these impacts on bivalves in wetlands. This study aims to investigate the impact of coastal environments on bivalves in riverine and coastal wetlands. We conducted field measurements of bivalves, water and sediment environments in Edogawa and Arakawa Rivers in 2010, in which a large-scale blue tide appeared around the head of Tokyo Bay. The results reveal that the wet weight of bivalves in the coastal wetland (Sanbanze) decreased more appreciably due to the blue tide than those in riverine wetland of the Edogawa River. Furthermore, we discussed the sediment and water environments at the station where the number of the bivalves in the riverine wetland increased after the blue tide.

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Barren ground is widely distributed in the sea area. The coastal structures to make the algae place have been constructed for about ten years. However, it is feared that the decrease in the effect of seaweed creation by the aged deterioration of the substrate and water temperature elevation in recent years. Field investigation concerning distribution of seaweed beds and physical environment were performed in fishing port of Hokkaido. In this study, the results of the field investigation are introduced. It is found that one of the causes is feeding pressure to seaweed by sea urchin. It is strongly dependent on water temperature in winter. To control the feeding pressure in the situation of the elevated water temperature, it is necessary to improve flow velocity by raising the rear steps.

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Granulated fly ash, one of recycled material, has been used as covering sands to improve sediment quality in enclosed coastal areas of Chugoku District. In the present study, in addition to reveal heavy metal contents of granulated fly ash, safety of the materials was examined using snails and bivalves in both laboratory experiments and field experiments. In the all experiments, bioaccumulation of heavy metals was not observed. Further, the heavy metal accumulation was lower in the body of animals used in the experiments than those sold in market. It was concluded that granulated fly ash is safety recycle material in terms of heavy metals for benthic animals.

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Tidal flats provide the function of water quality improvement by removing nutrients from the water. The aim of this study is to measure the role of tidal flat on water quality improvement in the Tokyo Port Wild Bird Park. Results from the field measurement show that (1) the tidal flat has a role of a source of the phosphorus and a sink of the nitrogen in summer, but a sink of the nitrogen and phosphorus in winter, (2) the tidal flat adsorbed of NO₃^- into the sediment and the release of PO₄⁺³ to the overlying water in both summer and winter, (3) the amount of removed nutrients by water birds is negative due to their excrement when the feeding rate is assumed as the rate of feeding action. (4) Denitrification and anammox formed in the sediment are thought to be major factors explaining the nitrogen removal by the tidal flat sediment.

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Investigation on the eelgrass Zostera japonica was conducted in order to collect scientific information for restoration of Z. japonica communities in tidal flats in urban coastal areas. The growth and survival properties of the Z. japonica and the environmental conditions were monitored at an existing eelgrass for several years. The morphological data has been showing a long-term tendency of rising due to accumulation of bed material, however, it was also observed that the movements of sediment were significant due to turbulence in bottom current. The formation of flowering shoot as well as the seed originated reproduction was considered to be prevented by the morphological disturbances. This suggested that the morphological control must be necessary to enhance the shoot growth and to preserve their seedlings.

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Concrete panels and blocks containing arginine,one of amino acid (AC) had been setting on the sea in three different harbors. The results of the study are as follows; (1) the quantity of microalga on the AC was three times larger than ordinary concrete (OC), and they were fed by an feeder after ten months. (2) On the AC, green algae such as Ulva or Cladophora grew thick after microalgae extinguishment. We observed that these seaweed was not contamination sources but feed resources for other creatures. (3) It is known that thick growth of small-sized chlorophyceae inhibits of large-sized seaweed. On the other hand, Crustose Corallines, frequently seen in "ISOYAKE" area, did not appear on the AC. This result to suggests that the concrete containing arginine can be used as base material for large-sized seaweed adhering.

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The persistent nature of intertidal sandbars was the subject of much speculation concerning the hydrodynamic mechanisms involved, but its origin remained enigmatic. We recently found on the basis of the geophysical evidence and theoretical modeling and analysis that the interplay between the effects of the dynamics of suction and sediment transport and morphology plays a crucial role in such intertidal sandbar morphodynamics. Here we further clarified this mechanism in light of artificially created sandbars in Tokyo Bay, by performing integrated observations and analyses of the morphological and geoenvironmental changes as well as the benthos diversity and stratigraphy variations, combined with a series of laboratory soil tests. The results highlight the salient geophysics that arise from the feedback between sediment transport and the suction dynamics effects, and give rise to an optimal design of such dynamically stable sandbars as habitats with diverse ecological activity.

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Field surveys and laboratory experiments were conducted in 2009 to 2010 to examine methods to reduce outbreaks of green tides by Ulva spp. at the north pond of Osaka Nanko bird sanctuary. The green-tide-forming seaweed varied depending on the season, and U. pertusa predominated at the bird sanctuary from early summer to autumn, while U. ohnoi was abundant there from autumn to early spring. The laboratory experiments revealed that exposure of U. ohnoi to air with low salinity inhibited their photosynthesis at 35℃. These results, along with the preceding result of experiments for U. pertusa suggest the possibility of controlling a green tide of U. ohnoi or U. pertusa by a combination of exposure to air for 3-5hours with low salinities of 15-20psu in summer.

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We examined the correlation between mud content, the index of the amount of sediment organic matter, and the index of the amount of sulfide with the number of species and populations of 4 phyla of benthos (Annelida, Arthropoda, Mollusca, and Echinodermata). The results reveal that the mud content, increase in organic matter levels and sulfide levels in the sediments, directly cause the decrease in the number of benthic species and populations.

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The excess deposition of organic matter impacts to the eco-systems in brackish water regions. Improving the environment is necessary to understand the deposition and transportation characteristics of organic matter. In this study, salinity effect to resuspension characteristics of organic mud was examined. From these results, a resuspension model which can consider the qualities of organic mud and water salinity was estimated. It was clarified that the calculated resuspension flux and grain size distribution using this model extremely replicate the measured data. Additionally, this model can grasp the particle size selection by salinity.

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We investigated the heavy metals contained in marine organisms and sediments at the Lyme Regis, a large landside occurred in May 2008, in southwest England. And protein biomarkers in the liver of the shellfish (L. littorea) were analyzed to consider the biological effects in vivo. As a result, the amount of heavy metals in sediment and seaweed (F. vesiculosus) around the landslide site was higher than none landslide site. Many elements had higher correlation coefficient between the sediments heavy metal and F. vesiculosus heavy metal. While the between the sediments heavy metal and L. littorea heavy metal were not high a correlation coefficient. How ever, the value of oxyradical biomarkers (TOSC) in the L. littorea was higher in the landslide site. Besides metal-protein (MT) tended to be higher in the TOSC as landslides at the site.

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Loss on ignition (LOI) has been widely used as a method to measure the amount of organic matter exists in organic mud. In this study, we investigate the ignition behavior of organic matter and inorganic matter through LOI test by altering the ignition temperature from 200 to 800℃ in order to find an appropriate ignition temperature for organic mud. Furthermore, carbon and nitrogen contents were also measured at each ignition temperature. As a result, it is obvious that organic matter is totally removed at 500℃ because carbon and nitrogen contents become equal to zero. In addition, we proposed an equation for estimation carbon and nitrogen contents in organic mud by using LOIs at 400℃ and 500℃.

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The long-term change of waves is known to have some kind of relation with the climate change. In order to project long-term wave change due to climate change requires the understanding of the relationship between wave climate and teleconnection pattern since climate variability has strong relations with teleconnection behavior. This study examined the influence of teleconnection on winter wave climate around Japan. The Western Pacific (WP) pattern has the most important effect on waves over the region. Under future global warming climate, the trend of WP would shift to positive, which indicates wave height reduction around Japan.

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One of fearful impacts to coastal zone in future is change in intensity of tropical cyclone on global warming. The purpose of this paper is projection of future storm surges due to the tropical cyclones and vulnerability assessments by the storm surges in coastal zones. Outputs of a global climate model were used for trend of change in the sea surfaced pressure of tropical cyclones. A numerical simulation was employed to project storm surges. Projected results showed future storm surges become higher along coasts of Gulf of Mexico and east coast of America, and East-Asian coasts facing to Pacific Ocean. The results of vulnerability assessment showed that change in intensity of tropical cyclone is big impact as same as impact of rise in sea level and population growth, particularly in Asia coastal zones.

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Future storm surge risk due to the tropical cyclones (TC) in East Asia is evaluated where the climate change projection by the state-of-the-art atmospheric GCM is employed as driving forces for storm surge simulations. The reproducibility or validity of TC characteristics by the GCM in the northwest Pacific is confirmed comparing with the observed best track data, and future TC change is presented. Storm surge simulations are carried out in the East Asia with the finest nested domain on Japanese coast. Probability of maximum storm surge heights with several return periods are analyzed by extreme statistics. It was found that there are strong regional dependencies on the change of magnitudes of severe storm surge anomalies in the future climate.

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The scarcity of tropical cyclone data causes the difficulty of external force estimation for coastal structures. The Stochastic Tropical cyclone Model (STM) is a useful method for overcoming this problem. We developed a global STM based on IBTrACS dataset and validated the model performance for statistics of tropical cyclone data. After that, the future change estimated from 8 different General Circulation Model projections under global warming scenarios was implemented in the STM. By using the STM, we estimated the future cyclone number and magnitude quantitatively.

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It has been discussed that intensity of typhoon may increase in the future due to climate change, resulting in severe coastal disasters. It is important to estimate the probable maximum magnitude of storm surges under the future climate for coastal disaster mitigation. In the present study, uncertainty of storm surge projection was discussed by employing the hundreds of different severe meteorological conditions generated by the potential vorticity inversion method. Ensemble numerical simulation results show the most hazardous typhoon track is different from most intense typhoon's one. Estimated maximum storm surge in the Tokyo bay was 1.4 m which is the same level as the historical highest record.

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We simulated typhoon surge around Osaka, Ise and Tokyo bays of typhoons for 10,000 years in each present and future climate. Their typhoons were reproduced by Yasuda(2010) using with a stochastic typhoon model. Yasuda projected typhoons in the future derived by super-high-resolution atmospheric models. In the beginning, we showed that the calculated surge of present climate stochastic typhoons comprised the other of recorded typhoon. Variations of each three bays which were located west to east projected totally similar but different in detail. Near the modal classes their frequencies was decreased, but over the more higher classes their frequencies were increased.

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The influence of global climate change due to green house effects on coastal environments will be required impact assessment, mitigation and adaptation strategies of beach morphology, breakwater design and so on. This study projects future change of coastal environmental forces based on the latest climate data set combining CMIP3 and high-resolution AGCM results. The global and regional coastal environmental forces such as sea surface temperature, sea level, sea level pressure, sea surface wind and ocean wave are analyzed using statistical down scaling and model ensemble method. The model ensemble-averaged means and their standard deviations of coastal environmental forces are presented from 2000 to 2100. There are clear long-term trends of coastal environmental forces depend on the region.

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Sea level rise due to climate change is expected to increase coastal erosion and thus result in serious coastal disasters. Along the Japanese coasts, existing projections of the sea level rise show 9-27 cm rise at the end of 21st century; however, there is few study on its effect on the Japanese coastal erosion after Mimura et al. (1994). In this study, observed wave and tidal data were analyzed to investigate characteristics of their long-term trends and then future beach erosion along the Japanese coasts was projected using the Bruun rule for SRES A1B scenario. The observed data analyses demonstrate that the annual average and maximum tide levels and the annual maximum wave height tended to increase at rates of 0.4, 0.4 and 3.9 cm/yr, respectively, in recent decades. Due to these factors, beach erosion was projected to be 10-50 m.

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The presence of sea ice in the polar regions plays an important role in the world's climate system, and it is therefore important to understand the process influencing the formation and deformation of ice fields. The objective of our research was to investigate characteristics of the thermodynamics of frazil and grease-pancake ice in a wave field. We used a wave tank installed in a cold room to generate grease-pancake ice. The surface temperature was measured by using an infrared thermography. We concluded that the water temperature and wave period are an important factor to determine the growing and evolving of frazil ice. Furthermore, the temperature of pancake periphery became higher than that of its center, which indicates that the heat of solidification is caused when the frazil ice froze to its periphery.

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We conducted laboratory experiments to monitor frazil/pancake ice growth from open water condition in an indoor wave tank cooled at -8 degree. Salt water with concentration of 35psu was used similar to ocean conditions. In the growth of frazil ice, the deposition thickness and the rise velocity were measured and in that of pancake ice, the size was recorded at 2 hours interval during about 16 hours, respectively. As a result, when whole sea water in the tank supercooled, the frazil ice is actively generated not only on surface but also in the deeper water. The maximum deposition thickness becomes about 6 mm per an hour. Finally, the sizes of pancake could be estimated by probability density function based on logarithmic normal distribution.

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GCM (Global Climate Model) outputs differ corresponding to models used, SRES (Special Report on Emissions Scenarios), and multiple realizations with variation in the initial conditions. The Climate Change Information Database was developed in order to compare various GCM dataset on any area of primary mesh (approximately 80 km x 80 km) for surface meteorological elements such as precipitation and temperature. The database is open to the public through the website, and users can display distribution map and reference chart with simple operation through a web browser. The database will make it easier to understand overview of the climate change simulated by GCM and impact assessment of global warming.

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Recently, it has become clear from observational evidence that global warming is progressing. In Japan, many coastal structures were designed in the late 1950s. In the future, coastal structures must be designed by taking into account the changes in forces accompanying with the future estimated changes in sea level rise and wave due to global warming. However, safety performance evaluation of coastal structures under future climate conditions is scare. This study evaluated the effects of changes of coastal environment factors on the safety performance of coastal structures by using a reliability method of Level 3, and proposes an adaptation method to keep the present safety level.

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In recent years, consideration of the environmental influence of coastal structures is becoming more important, because of the huge consumption of materials and large amount of greenhouse gas resulting from construction. Technological innovation to reduce the environmental load to the earth and a method to estimate this load are required. The purpose of this study is to evaluate the environmental effects of coastal structures using concrete armor blocks, especially focusing on the reduction of the amount of greenhouse gas resulting from the production and transportation of the materials and during the construction from manufacturing to placement of the blocks. It is concluded that the new armor block is very effective to reduce environmental load.

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Winds and waves for the design of floating type wind farm were evaluated by using variuous kinds of re-analysis and prediction data including NCEP wind data, JMA meteorological data, NEDO data and Hourly GPV data. Statistical values of winds and waves for several return periods were obtained. Wave characteristics were determined for maximum wave height, crest height, 2D height-period distribution, wave energy spectrum and so on. Tide, tidal current and wind-induced current were also evaluated.

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This study aims development of wave power generation system using wave energy in coastal zone. A wave power generation system using a vertical slit type breakwater widely used in Japanese ports and harbors is proposed by installing an improved Savonius windmill in a chamber of the breakwater. Laboratory experiment was carried out to examine the characteristics of power generation by measurement of the rotational speed and the torque of the windmill. According to the measurement results, the relationship between obtained power and wave condition was discussed. The effect of installing the windmill in a chamber of the breakwater on wave reflection was also discussed.

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Eutrophication is a serious problem in Tokyo Bay environment. As a result, hypoxic water mass occurs every year from spring to autumn. Since sea bass, caught in a trawl fishery in the bay, try to avoid hypoxic water mass, spatial distribution of DO in the bottom layer is the key information for the fishery. We thus developed a nowcast/forecast system for the bottom layer DO distribution coupling a coastal circulation model and an ecosystem model. We then enhanced the system with the assimilation of monitoring data, which is validated through the comparison between computation and measurements. Positions of sea bass catch and border of hypoxic water mass matched and the usefulness of the system have been confirmed.

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This paper considers that recognition about young people, Japan. Recently, the natural disaster increases and it is generated frequently in Japan. For reduction of natural disaster damage, it is utilizing both hardware and software sides. However, disaster prevention technology using hardware is not so advanced from the problem on the budget side. Therefore, it is important to use disaster prevention technology using software like hazard map and information propagation and method to visualize the tsunami and storm surge by the hydraulic model.
In this study, the questionnaire survey of the understanding level to people's hazard maps, the ideas, and the disaster and disaster recognition was executed. Finally, it is examined to effective use of the hazard map and idea of disaster recognition in the future.

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A person in a shallow beach near shoreline at Moheji Coast in Hokkaido died due to wave that had ordinary height in November, 2008. In order to reproduce the situation of the fall accident in a shallow beach, two-dimensional hydraulic model tests and numerical calculation were carried out to examine the wave force on a human body. The fall limit ratio was newly proposed for estimating the qualitative risk of person's fall accidents, and its applicability was confirmed. Based on these results, possibilities of person's fall accidents with ordinary waves were confirmed, and the safety tide level was shown for some wave conditions. A basic idea of the safety management was also proposed for shallow beach.

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